Rheonetic Magnetic Paste

The substance inside this set of syringes is something called a magnetorheological fluid or MR fluid. MR fluid is a liquid that consists of a carrier medium – most commonly mineral oil or silicone oil – and a suspension of magnetically polarisable particles – often iron – that responds to a magnetic field with a dramatic change in its viscosity and elasticity, instantly turning into a solid on contact with a magnet. This effect can be controlled quite accurately by varying the intensity of the magnetic field.

MR fluid is similar to ferro fluid (we also have a sample of this in the collection), but ferro fluid is composed of much smaller, nano-scale particles. Unfortunately, because the particles suspended in this MR fluid are larger and relatively heavy they settle if they are not moved around and remixed, and this sample has sedimented over time to the extent that it will now not revert to a liquid when the magnet is removed.

These MR fluids were initially discovered and developed in the 1940s, but after an initial flurry of interest they were largely forgotten about, and haven’t found many commercial applications until recently. Researchers have explored the use of these substances for military uses, with the idea that they could turn soft clothing into durable armour in seconds with a magnetic field. These substances are currently used in the suspension systems of heavy goods and all-terrain vehicles as dynamic shock-absorbers that, unlike plain oil or water, can be adjusted according to the driver’s preference, the weight of the load carried and the kind of terrain being driven on.